It depends on what we would get for free, if there would be still an optional subscription plan and what you would get for it, as well as whether or not they expanded the micro-transaction store. A lot of these “free” mmo’s often turn into games where you get for little for free and then have to keep shelling out clams for run of the mill stuff like multiple characters, more than three character options, and leveling past the starter zones. Having no subscription fees also allows for an entire population of goldsellers and spammers to create accounts without having to even pay for a subscription, whereas currently they have to recreate ten-day trials or steal other people’s accounts. It’s a common problem on a lot of the free mmo’s out there. Mabinogi is apparently plagued with this kind of thing.

Of course that’s not to say that with careful grooming and a well-handled transition a “free” option could not be implemented. DDO has been handling it quite nicely. It’s just that changing your subscription model complicates a great many facets of the game and can result in a decrease of quality as well as cost to the player.